Physical vapor deposition of doped transition metal oxide and post-deposition treatment thereof for non-volatile memory applications

Abstract

Embodiments of methods for depositing doped transition metal oxides are provided herein. In some embodiments, a method of depositing a doped transition metal oxide layer includes: sputtering a first target comprising a transition metal while providing a source of oxygen atoms; sputtering a second target comprising a dopant element; and forming a doped transition metal oxide layer on a substrate from the sputtered transition metal, oxygen atoms, and dopant element. The first target can be formed from a transition metal or a transition metal oxide.

1 . A method of depositing a doped transition metal oxide layer, comprising:
 sputtering a first target comprising a transition metal while providing a source of oxygen atoms;   sputtering a second target comprising a dopant element; and   forming a doped transition metal oxide layer on a substrate from the sputtered transition metal, oxygen atoms, and dopant element.   
     
     
         2 . The method of  claim 1 , wherein the first target comprises nickel, tantalum, vanadium, zirconium, or a corresponding metal oxide thereof. 
     
     
         3 . The method of  claim 1 , wherein the dopant element comprises carbon, tungsten, or titanium. 
     
     
         4 . The method of  claim 1 , wherein the doped transition metal oxide comprises NiO/C, NiO/CW, V 2 O 3 /C, V 2 O 3 /Ti, V 2 O 3 /CTi, or ZrO/C. 
     
     
         5 . The method of  claim 1 , where the source of oxygen atoms is oxygen gas. 
     
     
         6 . The method of  claim 1 , wherein the first target further comprises oxygen, and wherein the source of oxygen atoms is the first target. 
     
     
         7 . The method of  claim 1 , wherein the first target and the second target are sputtered at the same time. 
     
     
         8 . The method of  claim 1 , wherein the doped transition metal oxide comprises NiO/C, and wherein the first target and the second target are sputtered at the same time. 
     
     
         9 . A method of depositing a doped transition metal oxide layer, comprising:
 depositing a first doped transition metal oxide layer atop a first metal layer on a substrate by sputtering a first target comprising a transition metal while providing a source of oxygen atoms and sputtering a second target comprising a dopant element; and   depositing a second doped transition metal oxide layer atop the first doped transition metal oxide by sputtering the first target while providing a source of oxygen atoms and sputtering the second target, wherein the stoichiometry of the first doped transition metal oxide is different than the stoichiometry of the second doped transition metal oxide.   
     
     
         10 . The method of  claim 9 , wherein the first metal layer comprises a first electrode of a non-volatile memory structure, and further comprising:
 depositing a second metal layer atop the second doped transition metal oxide layer, wherein the second metal layer comprises a second electrode of the non-volatile memory structure.   
     
     
         11 . The method of  claim 10 , wherein the second metal layer is deposited in the same chamber as the first and second doped transition metal oxide layers. 
     
     
         12 . The method of  claim 10 , further comprising:
 annealing the first metal layer, first doped transition metal oxide layer, second doped transition metal oxide layer, and the second metal layer.   
     
     
         13 . The method of  claim 10 , wherein the first and second metal layers comprise W, TaN, Ir, or Pt. 
     
     
         14 . The method of  claim 9 , further comprising:
 depositing a seed layer atop the first metal layer, prior to depositing the first doped transition metal oxide layer.   
     
     
         15 . The method of  claim 14 , further comprising:
 annealing the seed layer prior to depositing the first doped transition metal oxide layer.   
     
     
         16 . The method of  claim 9 , further comprising:
 depositing a third doped transition metal oxide layer atop the second doped transition metal oxide layer, wherein the stoichiometry of the third doped transition metal oxide is different than the stoichiometry of the second doped transition metal oxide.   
     
     
         17 . The method of  claim 9 , further comprising:
 varying the stoichiometry of the first doped transition metal oxide during deposition of the first doped transition metal oxide layer to gradually match the stoichiometry of the second doped transition metal oxide.   
     
     
         18 . A method of depositing a doped transition metal oxide layer, comprising:
 depositing a first doped transition metal oxide layer atop a first metal layer on a substrate by sputtering a first target comprising a transition metal while providing a source of oxygen atoms and sputtering a second target comprising a dopant element;   depositing a second doped transition metal oxide layer atop the first doped transition metal oxide by sputtering the first target while providing a source of oxygen atoms and sputtering the second target, wherein the stoichiometry of the first doped transition metal oxide is different than the stoichiometry of the second doped transition metal oxide; and   depositing a second metal layer atop the second doped transition metal oxide layer, wherein the first metal layer comprises a first electrode of a non-volatile memory structure, the first doped transition metal oxide layer comprises a buffer layer of the non-volatile memory structure, the second doped transition metal oxide layer comprises a switching layer of the non-volatile memory structure, and the second metal layer comprises a second electrode of the non-volatile memory structure.   
     
     
         19 . The method of  claim 18 , further comprising:
 depositing a third doped transition metal oxide layer atop the second doped transition metal oxide layer, wherein the stoichiometry of the third doped transition metal oxide is different than the stoichiometry of the second doped transition metal oxide, and wherein the third doped transition metal oxide layer comprises a second buffer layer of the non-volatile memory structure.   
     
     
         20 . The method of  claim 18 , wherein the doped transition metal oxide comprises NiO/C, NiO/CW, V 2 O 3 /C, V 2 O 3 /Ti, V 2 O 3 /CTi, or ZrO/C.